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    tty: fix tty_line must not be equal to number of allocated tty pointers in tty driver · 6eb68d6f
    Nathael Pajani 提交于
    I found a bug "by chance" in drivers/char/tty_io.c
    
    I mean "by chance" because I was just reading the code of the
    tty_find_polling_driver() to make a new tty_find_by_name() function.
    
    In tty_find_polling_driver() the driver actually test "tty_line <=
    p->num" while num refers to the number of struct tty_struct pointers
    allocated for the p->ttys (p is a tty_driver), and tty_line is scanned
    in a tty name, which can be for example ttyS2. Then tty_line equals 2.
    And if p->num is 2, we have only p->ttys[0] and p->ttys[1], but no
    p->ttys[2].
    
    This is actually unharmful, for tty_find_polling_driver() is used only
    in drivers/serial/kgdboc.c, and there's a test over there to find a
    console with a matching index, which will never happen.
    
    This is still a bug anyway.
    Signed-off-by: NNathael Pajani <nathael.pajani@ed3l.fr>
    Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>
    6eb68d6f
tty_io.c 78.7 KB